The phrase "Gleaming the Cube" referred to a very difficult skateboarding move in the movie. In reality the term was made up for the movie. I don't recall being impressed when Slater's character "gleams the cube". I believe a move was eventually named after the movie and I don't think it was what Slater did in the movie. The real skaters in the movie do put on a fine display of tricks and stunts throughout the film.

Christian Slater plays Brian Kelly whose brother dies and he has to avenge his brother's death and avoid the cops with some nifty skating. Standard Evil Company versus a bunch of do-gooder kids. Brian's brother is killed when he discovers his company is smuggling weapons instead of selling medicine. His death is made to look like a suicide. Brian knows this isn't true and tries to tell the police, but of course they don't believe him, because he is just a slacker/skateboarder/trouble maker. So Brian and his friends must use all their skating skills to avoid both the cops and the bad guys while trying to expose the weapon smugglers.

A good movie to see if you are into skateboarding's past. I'd watch it again for nostalgia’s sake if I saw it on HBO or something.